Most electronic devices are now packaged with their electronic components mounted on printed circuit boards ("PCB"). PCBs have electrically conductive leads that are often connected to electrically conductive pads upon which surface mounted devices ("SMDs") can be mounted. Typically, these SMDs are resistors or capacitors. However, SMDs can also be inductors, "jumpers" (which short circuit two points), or other electrical components known to those of ordinary skill in the art. Generally, the electrical element of an SMD is carried within a ceramic or plastic package having two conductive end portions (connected internally through the electrical element) and a nonconductive center portion. To permanently connect the SMD electrically to the PCB, its conductive end portions are soldered to appropriately spaced conductive pads provided on the surface of the PCB.
Problems can arise, if known conductive pads are used, when one attempts to change the size of an SMD, for example, due to design requirements or the desire to substitute one SMD for another. For instance, it may be desired to change from the use of a large SMD (e.g., a 1206 SMD) to a small SMD (e.g., an 0805 SMD). Originally, for a large SMD, the conductive pads of the PCB would have to be larger than some minimum size in order to properly solder the conductive end portions of the SMD to the pads. However, if production changes to use a small SMD, problems arise due to the conductive pads being too big and spaced too far apart for the smaller SMD. This may result in excess solder being deposited to connect the first conductive pad of the PCB to the first conductive end portion of the small SMD and the second conductive pad to the second conductive end portion. Quite often there will be enough excess solder to bridge the gap between the conductive pads, shorting them together. If this happens, the SMD's component (i.e., resistor, capacitor, inductor, etc.) is shorted and cannot perform its intended function. Those of ordinary skill in the art will appreciate that even if the SMD is to merely serve as a jumper, a problem may arise, because excess solder could short together two electrically conductive paths that were not intended to be shorted together.
A manufacturer may use the original, large SMDs, despite a desire to substitute a smaller SMD, or may redesign the PCB with smaller more closely spaced conductive pads to better accommodate the small SMDs. The first choice simply forgoes an opportunity to substitute the smaller chip. The second choice, in addition to requiring potentially costly redesign of the PCB layout, renders any large SMD inventory a loss if production of the new PCBs redesigned for using the small SMDs starts prior to the total depletion of the large SMD inventory.